And he's an idiot. 47% of Americans don't pay income tax. Because they are too poor. They still pay a lot of other taxes.
Sales taxes, property taxes, and excise taxes tend to be regressive, and fall harder on the poor. There is really no reason for poor people to pay income tax.
Not to mention that living costs (in terms of cost of capital, and even day-to-day expenses like food) tend to be higher in poorer neighborhoods. Don't believe me? Go into any bad neighborhood and note the proliferation of payday loan operations, pawn shops, bodegas/convenience stores, and the relative lack of supermarkets (where food tends to be cheaper) and regular banks.